In many organizations, group communications (i.e., point-to-multipoint connections) are very important in a radio communications system. These point-to-multipoint connections provide groups with day-to-day communications and are used to coordinate operations and the distribution of information where a large number of users are working together toward a common goal, for instance in situations involving public safety.
Communications groups or communities, e.g. “talk groups,” can be created within a radio system to correspond to organizational and operational needs. With respect to a talk group, this type of community typically comprises a group identifier, a list of participants and a coverage area, and changing either the user list or coverage area creates a new group identified by a new number. Moreover, talk groups are, typically, established a priori by a system administrator such as, for instance, a dispatcher or commander, based on parameters such as work teams. However, occasionally situations may arise, for instance during a crisis, that necessitate the dynamic allocation of one or more talk groups, for instance to enable talk groups to communicate that normally would not have the capability of communicating.
Consider the example of a network used by several different organizations with coverage extending over towns A and B. Agencies in the area may include a regional utility, two local police departments and two local fire departments (i.e., one fire and one police department for each town). During normal operation in town A, the local police and fire departments operate across the entire municipality using talk groups 1 and 2, respectively. In town B, the local police and fire departments operate across the entire municipality using talk groups 3 and 4, respectively. The regional utility operates across both towns A and B using a talk group 5. If an accident or emergency situation should occur that required a response by all of the above mentioned organizations, it would be useful to dynamically allocate a talk group that would include at least a portion of the participants in each of the talk groups 1 through 5.
It is known that the dispatcher or commander may allocate a relevant talk group as a function of response needs generated by the emergency situation. The dispatcher or commander may define the group, for instance, as a function of the communications devices identified as being in a relevant geographical area that is within a predetermined radius of the emergency location. A disadvantage of this method of dynamically allocating a talk group is that it necessitates control by a human operator, thereby, subjecting this methodology to human error and delay. A further disadvantage of this method of dynamically allocating a talk group is that it is not possible to create talk groups for sub teams within an incident scene, or automated ad hoc talk group establishment based on scene convergence.
Thus, there exists a need for a means of dynamically determining a community of entities in a communications system without the need for human intervention. It is also desirable that this method utilize a density function computation.